1/* 2 * Copyright (C) 2005 Junio C Hamano 3 */ 4#include "cache.h" 5#include "diff.h" 6#include "diffcore.h" 7#include "hashmap.h" 8#include "progress.h" 9 10/* Table of rename/copy destinations */ 11 12static struct diff_rename_dst { 13 struct diff_filespec *two; 14 struct diff_filepair *pair; 15} *rename_dst; 16static int rename_dst_nr, rename_dst_alloc; 17 18static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two, 19 int insert_ok) 20{ 21 int first, last; 22 23 first = 0; 24 last = rename_dst_nr; 25 while (last > first) { 26 int next = (last + first) >> 1; 27 struct diff_rename_dst *dst = &(rename_dst[next]); 28 int cmp = strcmp(two->path, dst->two->path); 29 if (!cmp) 30 return dst; 31 if (cmp < 0) { 32 last = next; 33 continue; 34 } 35 first = next+1; 36 } 37 /* not found */ 38 if (!insert_ok) 39 return NULL; 40 /* insert to make it at "first" */ 41 ALLOC_GROW(rename_dst, rename_dst_nr + 1, rename_dst_alloc); 42 rename_dst_nr++; 43 if (first < rename_dst_nr) 44 memmove(rename_dst + first + 1, rename_dst + first, 45 (rename_dst_nr - first - 1) * sizeof(*rename_dst)); 46 rename_dst[first].two = alloc_filespec(two->path); 47 fill_filespec(rename_dst[first].two, two->sha1, two->sha1_valid, two->mode); 48 rename_dst[first].pair = NULL; 49 return &(rename_dst[first]); 50} 51 52/* Table of rename/copy src files */ 53static struct diff_rename_src { 54 struct diff_filepair *p; 55 unsigned short score; /* to remember the break score */ 56} *rename_src; 57static int rename_src_nr, rename_src_alloc; 58 59static struct diff_rename_src *register_rename_src(struct diff_filepair *p) 60{ 61 int first, last; 62 struct diff_filespec *one = p->one; 63 unsigned short score = p->score; 64 65 first = 0; 66 last = rename_src_nr; 67 while (last > first) { 68 int next = (last + first) >> 1; 69 struct diff_rename_src *src = &(rename_src[next]); 70 int cmp = strcmp(one->path, src->p->one->path); 71 if (!cmp) 72 return src; 73 if (cmp < 0) { 74 last = next; 75 continue; 76 } 77 first = next+1; 78 } 79 80 /* insert to make it at "first" */ 81 ALLOC_GROW(rename_src, rename_src_nr + 1, rename_src_alloc); 82 rename_src_nr++; 83 if (first < rename_src_nr) 84 memmove(rename_src + first + 1, rename_src + first, 85 (rename_src_nr - first - 1) * sizeof(*rename_src)); 86 rename_src[first].p = p; 87 rename_src[first].score = score; 88 return &(rename_src[first]); 89} 90 91static int basename_same(struct diff_filespec *src, struct diff_filespec *dst) 92{ 93 int src_len = strlen(src->path), dst_len = strlen(dst->path); 94 while (src_len && dst_len) { 95 char c1 = src->path[--src_len]; 96 char c2 = dst->path[--dst_len]; 97 if (c1 != c2) 98 return 0; 99 if (c1 == '/') 100 return 1; 101 } 102 return (!src_len || src->path[src_len - 1] == '/') && 103 (!dst_len || dst->path[dst_len - 1] == '/'); 104} 105 106struct diff_score { 107 int src; /* index in rename_src */ 108 int dst; /* index in rename_dst */ 109 unsigned short score; 110 short name_score; 111}; 112 113static int estimate_similarity(struct diff_filespec *src, 114 struct diff_filespec *dst, 115 int minimum_score) 116{ 117 /* src points at a file that existed in the original tree (or 118 * optionally a file in the destination tree) and dst points 119 * at a newly created file. They may be quite similar, in which 120 * case we want to say src is renamed to dst or src is copied into 121 * dst, and then some edit has been applied to dst. 122 * 123 * Compare them and return how similar they are, representing 124 * the score as an integer between 0 and MAX_SCORE. 125 * 126 * When there is an exact match, it is considered a better 127 * match than anything else; the destination does not even 128 * call into this function in that case. 129 */ 130 unsigned long max_size, delta_size, base_size, src_copied, literal_added; 131 unsigned long delta_limit; 132 int score; 133 134 /* We deal only with regular files. Symlink renames are handled 135 * only when they are exact matches --- in other words, no edits 136 * after renaming. 137 */ 138 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode)) 139 return 0; 140 141 /* 142 * Need to check that source and destination sizes are 143 * filled in before comparing them. 144 * 145 * If we already have "cnt_data" filled in, we know it's 146 * all good (avoid checking the size for zero, as that 147 * is a possible size - we really should have a flag to 148 * say whether the size is valid or not!) 149 */ 150 if (!src->cnt_data && diff_populate_filespec(src, 1)) 151 return 0; 152 if (!dst->cnt_data && diff_populate_filespec(dst, 1)) 153 return 0; 154 155 max_size = ((src->size > dst->size) ? src->size : dst->size); 156 base_size = ((src->size < dst->size) ? src->size : dst->size); 157 delta_size = max_size - base_size; 158 159 /* We would not consider edits that change the file size so 160 * drastically. delta_size must be smaller than 161 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size). 162 * 163 * Note that base_size == 0 case is handled here already 164 * and the final score computation below would not have a 165 * divide-by-zero issue. 166 */ 167 if (max_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) 168 return 0; 169 170 if (!src->cnt_data && diff_populate_filespec(src, 0)) 171 return 0; 172 if (!dst->cnt_data && diff_populate_filespec(dst, 0)) 173 return 0; 174 175 delta_limit = (unsigned long) 176 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE); 177 if (diffcore_count_changes(src, dst, 178 &src->cnt_data, &dst->cnt_data, 179 delta_limit, 180 &src_copied, &literal_added)) 181 return 0; 182 183 /* How similar are they? 184 * what percentage of material in dst are from source? 185 */ 186 if (!dst->size) 187 score = 0; /* should not happen */ 188 else 189 score = (int)(src_copied * MAX_SCORE / max_size); 190 return score; 191} 192 193static void record_rename_pair(int dst_index, int src_index, int score) 194{ 195 struct diff_filespec *src, *dst; 196 struct diff_filepair *dp; 197 198 if (rename_dst[dst_index].pair) 199 die("internal error: dst already matched."); 200 201 src = rename_src[src_index].p->one; 202 src->rename_used++; 203 src->count++; 204 205 dst = rename_dst[dst_index].two; 206 dst->count++; 207 208 dp = diff_queue(NULL, src, dst); 209 dp->renamed_pair = 1; 210 if (!strcmp(src->path, dst->path)) 211 dp->score = rename_src[src_index].score; 212 else 213 dp->score = score; 214 rename_dst[dst_index].pair = dp; 215} 216 217/* 218 * We sort the rename similarity matrix with the score, in descending 219 * order (the most similar first). 220 */ 221static int score_compare(const void *a_, const void *b_) 222{ 223 const struct diff_score *a = a_, *b = b_; 224 225 /* sink the unused ones to the bottom */ 226 if (a->dst < 0) 227 return (0 <= b->dst); 228 else if (b->dst < 0) 229 return -1; 230 231 if (a->score == b->score) 232 return b->name_score - a->name_score; 233 234 return b->score - a->score; 235} 236 237struct file_similarity { 238 struct hashmap_entry entry; 239 int index; 240 struct diff_filespec *filespec; 241}; 242 243static unsigned int hash_filespec(struct diff_filespec *filespec) 244{ 245 unsigned int hash; 246 if (!filespec->sha1_valid) { 247 if (diff_populate_filespec(filespec, 0)) 248 return 0; 249 hash_sha1_file(filespec->data, filespec->size, "blob", filespec->sha1); 250 } 251 memcpy(&hash, filespec->sha1, sizeof(hash)); 252 return hash; 253} 254 255static int find_identical_files(struct hashmap *srcs, 256 int dst_index, 257 struct diff_options *options) 258{ 259 int renames = 0; 260 261 struct diff_filespec *target = rename_dst[dst_index].two; 262 struct file_similarity *p, *best, dst; 263 int i = 100, best_score = -1; 264 265 /* 266 * Find the best source match for specified destination. 267 */ 268 best = NULL; 269 hashmap_entry_init(&dst, hash_filespec(target)); 270 for (p = hashmap_get(srcs, &dst, NULL); p; p = hashmap_get_next(srcs, p)) { 271 int score; 272 struct diff_filespec *source = p->filespec; 273 274 /* False hash collision? */ 275 if (hashcmp(source->sha1, target->sha1)) 276 continue; 277 /* Non-regular files? If so, the modes must match! */ 278 if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) { 279 if (source->mode != target->mode) 280 continue; 281 } 282 /* Give higher scores to sources that haven't been used already */ 283 score = !source->rename_used; 284 if (source->rename_used && options->detect_rename != DIFF_DETECT_COPY) 285 continue; 286 score += basename_same(source, target); 287 if (score > best_score) { 288 best = p; 289 best_score = score; 290 if (score == 2) 291 break; 292 } 293 294 /* Too many identical alternatives? Pick one */ 295 if (!--i) 296 break; 297 } 298 if (best) { 299 record_rename_pair(dst_index, best->index, MAX_SCORE); 300 renames++; 301 } 302 return renames; 303} 304 305static void insert_file_table(struct hashmap *table, int index, struct diff_filespec *filespec) 306{ 307 struct file_similarity *entry = xmalloc(sizeof(*entry)); 308 309 entry->index = index; 310 entry->filespec = filespec; 311 312 hashmap_entry_init(entry, hash_filespec(filespec)); 313 hashmap_add(table, entry); 314} 315 316/* 317 * Find exact renames first. 318 * 319 * The first round matches up the up-to-date entries, 320 * and then during the second round we try to match 321 * cache-dirty entries as well. 322 */ 323static int find_exact_renames(struct diff_options *options) 324{ 325 int i, renames = 0; 326 struct hashmap file_table; 327 328 /* Add all sources to the hash table */ 329 hashmap_init(&file_table, NULL, rename_src_nr); 330 for (i = 0; i < rename_src_nr; i++) 331 insert_file_table(&file_table, i, rename_src[i].p->one); 332 333 /* Walk the destinations and find best source match */ 334 for (i = 0; i < rename_dst_nr; i++) 335 renames += find_identical_files(&file_table, i, options); 336 337 /* Free the hash data structure and entries */ 338 hashmap_free(&file_table, 1); 339 340 return renames; 341} 342 343#define NUM_CANDIDATE_PER_DST 4 344static void record_if_better(struct diff_score m[], struct diff_score *o) 345{ 346 int i, worst; 347 348 /* find the worst one */ 349 worst = 0; 350 for (i = 1; i < NUM_CANDIDATE_PER_DST; i++) 351 if (score_compare(&m[i], &m[worst]) > 0) 352 worst = i; 353 354 /* is it better than the worst one? */ 355 if (score_compare(&m[worst], o) > 0) 356 m[worst] = *o; 357} 358 359/* 360 * Returns: 361 * 0 if we are under the limit; 362 * 1 if we need to disable inexact rename detection; 363 * 2 if we would be under the limit if we were given -C instead of -C -C. 364 */ 365static int too_many_rename_candidates(int num_create, 366 struct diff_options *options) 367{ 368 int rename_limit = options->rename_limit; 369 int num_src = rename_src_nr; 370 int i; 371 372 options->needed_rename_limit = 0; 373 374 /* 375 * This basically does a test for the rename matrix not 376 * growing larger than a "rename_limit" square matrix, ie: 377 * 378 * num_create * num_src > rename_limit * rename_limit 379 * 380 * but handles the potential overflow case specially (and we 381 * assume at least 32-bit integers) 382 */ 383 if (rename_limit <= 0 || rename_limit > 32767) 384 rename_limit = 32767; 385 if ((num_create <= rename_limit || num_src <= rename_limit) && 386 (num_create * num_src <= rename_limit * rename_limit)) 387 return 0; 388 389 options->needed_rename_limit = 390 num_src > num_create ? num_src : num_create; 391 392 /* Are we running under -C -C? */ 393 if (!DIFF_OPT_TST(options, FIND_COPIES_HARDER)) 394 return 1; 395 396 /* Would we bust the limit if we were running under -C? */ 397 for (num_src = i = 0; i < rename_src_nr; i++) { 398 if (diff_unmodified_pair(rename_src[i].p)) 399 continue; 400 num_src++; 401 } 402 if ((num_create <= rename_limit || num_src <= rename_limit) && 403 (num_create * num_src <= rename_limit * rename_limit)) 404 return 2; 405 return 1; 406} 407 408static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, int copies) 409{ 410 int count = 0, i; 411 412 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) { 413 struct diff_rename_dst *dst; 414 415 if ((mx[i].dst < 0) || 416 (mx[i].score < minimum_score)) 417 break; /* there is no more usable pair. */ 418 dst = &rename_dst[mx[i].dst]; 419 if (dst->pair) 420 continue; /* already done, either exact or fuzzy. */ 421 if (!copies && rename_src[mx[i].src].p->one->rename_used) 422 continue; 423 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 424 count++; 425 } 426 return count; 427} 428 429void diffcore_rename(struct diff_options *options) 430{ 431 int detect_rename = options->detect_rename; 432 int minimum_score = options->rename_score; 433 struct diff_queue_struct *q = &diff_queued_diff; 434 struct diff_queue_struct outq; 435 struct diff_score *mx; 436 int i, j, rename_count, skip_unmodified = 0; 437 int num_create, dst_cnt; 438 struct progress *progress = NULL; 439 440 if (!minimum_score) 441 minimum_score = DEFAULT_RENAME_SCORE; 442 443 for (i = 0; i < q->nr; i++) { 444 struct diff_filepair *p = q->queue[i]; 445 if (!DIFF_FILE_VALID(p->one)) { 446 if (!DIFF_FILE_VALID(p->two)) 447 continue; /* unmerged */ 448 else if (options->single_follow && 449 strcmp(options->single_follow, p->two->path)) 450 continue; /* not interested */ 451 else if (!DIFF_OPT_TST(options, RENAME_EMPTY) && 452 is_empty_blob_sha1(p->two->sha1)) 453 continue; 454 else 455 locate_rename_dst(p->two, 1); 456 } 457 else if (!DIFF_OPT_TST(options, RENAME_EMPTY) && 458 is_empty_blob_sha1(p->one->sha1)) 459 continue; 460 else if (!DIFF_PAIR_UNMERGED(p) && !DIFF_FILE_VALID(p->two)) { 461 /* 462 * If the source is a broken "delete", and 463 * they did not really want to get broken, 464 * that means the source actually stays. 465 * So we increment the "rename_used" score 466 * by one, to indicate ourselves as a user 467 */ 468 if (p->broken_pair && !p->score) 469 p->one->rename_used++; 470 register_rename_src(p); 471 } 472 else if (detect_rename == DIFF_DETECT_COPY) { 473 /* 474 * Increment the "rename_used" score by 475 * one, to indicate ourselves as a user. 476 */ 477 p->one->rename_used++; 478 register_rename_src(p); 479 } 480 } 481 if (rename_dst_nr == 0 || rename_src_nr == 0) 482 goto cleanup; /* nothing to do */ 483 484 /* 485 * We really want to cull the candidates list early 486 * with cheap tests in order to avoid doing deltas. 487 */ 488 rename_count = find_exact_renames(options); 489 490 /* Did we only want exact renames? */ 491 if (minimum_score == MAX_SCORE) 492 goto cleanup; 493 494 /* 495 * Calculate how many renames are left (but all the source 496 * files still remain as options for rename/copies!) 497 */ 498 num_create = (rename_dst_nr - rename_count); 499 500 /* All done? */ 501 if (!num_create) 502 goto cleanup; 503 504 switch (too_many_rename_candidates(num_create, options)) { 505 case 1: 506 goto cleanup; 507 case 2: 508 options->degraded_cc_to_c = 1; 509 skip_unmodified = 1; 510 break; 511 default: 512 break; 513 } 514 515 if (options->show_rename_progress) { 516 progress = start_progress_delay( 517 _("Performing inexact rename detection"), 518 rename_dst_nr * rename_src_nr, 50, 1); 519 } 520 521 mx = xcalloc(num_create * NUM_CANDIDATE_PER_DST, sizeof(*mx)); 522 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 523 struct diff_filespec *two = rename_dst[i].two; 524 struct diff_score *m; 525 526 if (rename_dst[i].pair) 527 continue; /* dealt with exact match already. */ 528 529 m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST]; 530 for (j = 0; j < NUM_CANDIDATE_PER_DST; j++) 531 m[j].dst = -1; 532 533 for (j = 0; j < rename_src_nr; j++) { 534 struct diff_filespec *one = rename_src[j].p->one; 535 struct diff_score this_src; 536 537 if (skip_unmodified && 538 diff_unmodified_pair(rename_src[j].p)) 539 continue; 540 541 this_src.score = estimate_similarity(one, two, 542 minimum_score); 543 this_src.name_score = basename_same(one, two); 544 this_src.dst = i; 545 this_src.src = j; 546 record_if_better(m, &this_src); 547 /* 548 * Once we run estimate_similarity, 549 * We do not need the text anymore. 550 */ 551 diff_free_filespec_blob(one); 552 diff_free_filespec_blob(two); 553 } 554 dst_cnt++; 555 display_progress(progress, (i+1)*rename_src_nr); 556 } 557 stop_progress(&progress); 558 559 /* cost matrix sorted by most to least similar pair */ 560 qsort(mx, dst_cnt * NUM_CANDIDATE_PER_DST, sizeof(*mx), score_compare); 561 562 rename_count += find_renames(mx, dst_cnt, minimum_score, 0); 563 if (detect_rename == DIFF_DETECT_COPY) 564 rename_count += find_renames(mx, dst_cnt, minimum_score, 1); 565 free(mx); 566 567 cleanup: 568 /* At this point, we have found some renames and copies and they 569 * are recorded in rename_dst. The original list is still in *q. 570 */ 571 DIFF_QUEUE_CLEAR(&outq); 572 for (i = 0; i < q->nr; i++) { 573 struct diff_filepair *p = q->queue[i]; 574 struct diff_filepair *pair_to_free = NULL; 575 576 if (DIFF_PAIR_UNMERGED(p)) { 577 diff_q(&outq, p); 578 } 579 else if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 580 /* 581 * Creation 582 * 583 * We would output this create record if it has 584 * not been turned into a rename/copy already. 585 */ 586 struct diff_rename_dst *dst = 587 locate_rename_dst(p->two, 0); 588 if (dst && dst->pair) { 589 diff_q(&outq, dst->pair); 590 pair_to_free = p; 591 } 592 else 593 /* no matching rename/copy source, so 594 * record this as a creation. 595 */ 596 diff_q(&outq, p); 597 } 598 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 599 /* 600 * Deletion 601 * 602 * We would output this delete record if: 603 * 604 * (1) this is a broken delete and the counterpart 605 * broken create remains in the output; or 606 * (2) this is not a broken delete, and rename_dst 607 * does not have a rename/copy to move p->one->path 608 * out of existence. 609 * 610 * Otherwise, the counterpart broken create 611 * has been turned into a rename-edit; or 612 * delete did not have a matching create to 613 * begin with. 614 */ 615 if (DIFF_PAIR_BROKEN(p)) { 616 /* broken delete */ 617 struct diff_rename_dst *dst = 618 locate_rename_dst(p->one, 0); 619 if (dst && dst->pair) 620 /* counterpart is now rename/copy */ 621 pair_to_free = p; 622 } 623 else { 624 if (p->one->rename_used) 625 /* this path remains */ 626 pair_to_free = p; 627 } 628 629 if (pair_to_free) 630 ; 631 else 632 diff_q(&outq, p); 633 } 634 else if (!diff_unmodified_pair(p)) 635 /* all the usual ones need to be kept */ 636 diff_q(&outq, p); 637 else 638 /* no need to keep unmodified pairs */ 639 pair_to_free = p; 640 641 if (pair_to_free) 642 diff_free_filepair(pair_to_free); 643 } 644 diff_debug_queue("done copying original", &outq); 645 646 free(q->queue); 647 *q = outq; 648 diff_debug_queue("done collapsing", q); 649 650 for (i = 0; i < rename_dst_nr; i++) 651 free_filespec(rename_dst[i].two); 652 653 free(rename_dst); 654 rename_dst = NULL; 655 rename_dst_nr = rename_dst_alloc = 0; 656 free(rename_src); 657 rename_src = NULL; 658 rename_src_nr = rename_src_alloc = 0; 659 return; 660}